1. Field of the Invention
The present invention relates to a device for determining the location of cooking utensils on a cooking hob comprising a plurality of electrically powered thermal cells (resistors) distributed below a heat-resistant surface (for example of glass ceramic) on which at least one cooking utensil for the heat treatment (for example cooking, heating or thawing) of a food contained therein, the thermal cells being disposed in matrix formation.
2. Description of the Related Art
On these cooking hobs, known as high versatility hobs, the cooking utensil or utensils can be located at any desired point on them, for example depending on the space available, on the user""s operating comfort, or even purely randomly. The heating elements which have to be operated depend on the position of the cooking utensil or utensils. Information relative to their position hence constitutes a basic element for the operation of a cooking hob of the considered type.
In WO 97/19298, information concerning this position is obtained by means for monitoring the thermal load associated with each of the heating elements. The drawback of such a solution is that it requires electrodes or similar means with relative cabling which, being located in proximity to the heating elements, is subjected to high temperature, to resist which it must be of dedicated type, and hence specific. To this must be added the fact that the large number of components and the complexity of the cabling represent costs which negatively affect the final cost of the product.
In co-pending U.S. patent application Ser. No. 09/981,035, filed Oct. 17, 2001, by Davide Gerola and Cristiano Pastore and assigned to the assignee of this application, relating to a cooking hob of matrix type describes, by way of example, a method for identifying the location of cooking utensils using a video camera which frames the cooking hob, and a touch-screen on which the cooking hob and the cooking utensils disposed on them appear. By touching with the finger the reproductions of these utensils on the screen, the user selects those heating elements underlying the cooking utensils. This although meritorious solution is complex and hence relatively costly besides having the drawback that the video camera is exposed to smoke and steam which can negatively affect its operability.
An object of the present invention is to provide a device for determining the position, and the form and size (with suitable resolution), of cooking utensils placed on a cooking hob comprising a matrix arrangement of a plurality of heating elements, in order to power those which effectively need to be powered, i.e. those below the utensil, the device being simple, reliable and economically advantageous by comprising components intended for, or already present for, other purposes.
This and further objects which will be more apparent from the ensuing detailed description are attained by a determination device in accordance with the teachings of the accompanying claims.